See below for the chat box. Join us each Thursday at 3 p.m. EDT for a live conversation with leading scientists and expert reporters.

Today's Topic

Astronomers are finding hundreds of planets orbiting stars[2] other than our sun, some of them not much bigger than Earth. It seems just a matter of time before scientists will find planets that are Earth's size. But when might we reasonably expect to discover "another Earth"? What will it take to find an Earth-like planet, and how will we tell if it could harbor life? For that matter, why all the excitement? What's the point to the centuries-long quest for life out there?

Join us on Thursday, 9 May, at 3 p.m. EDT on this page for a live Google Hangout when we address these questions. Be sure to leave your questions for our guests in the comment box below.

Sara Seager is an astrophysicist and planetary scientist at MIT focusing on theoretical models of atmospheres and interiors of all kinds of exoplanets. Her research has introduced many new ideas to the field of exoplanet characterization, including work that led to the first detection of an exoplanet atmosphere.

Steven J. Dick

Steven J. Dick has recently been named the second Baruch S. Blumberg NASA/Library of Congress Chair in Astrobiology. He served as the Charles A. Lindbergh Chair in Aerospace History at the National Air and Space Museum from 2011-2012, as the NASA Chief Historian and Director of the NASA History Office from 2003-2009, and prior to that as an astronomer and historian of science at the U. S. Naval Observatory.

Moderator

Richard Kerr

After stealthily taking a couple of journalism classes, a job ad for covering geophysics at Science popped up. A week after defending his dissertation in 1977, Dick found himself in D.C. as a bona fide science writer.